Horsepower with mileage options

Cam and gears are main part to get a balance of performance and mileage.

Theres a sweet spot. EG.. Like the 340 cam over 318 cam will give a good boost in performance with little to no hit in mpg but going a couple steps up from might kill mileage with little useful gain in power.

I wouldn't go 2 bbl. The factory didn't use them for better mileage just cheaper to build. Your only gonna run on the front barrels most of the time anyways.

Modern cars mainly make power from good flowing heads (plus intake/exhaust systems) and mild cam plus OD.
Unlike most modified engines that use lot of cam to try to squeeze all the performance out.

The only problem say puting eddy heads on with a 340 cam is you'll be leaving a lot of power on the table. But you'll have a better behaved and fuel mileage engine then going with poor flowing heads and a big cam to get the same power.

Hydraulic roller and 1.6 rockers are good way to. Since you can get more lift with less duration.